1. Field of the Invention
This invention relates to an action-changing structure for motion toys, and a motion toy using this action-changing structure, the action-changing structure being adapted to automatically changing the action of a motion toy, this action-changing operation enabling a motion toy to make various kinds of actions.
2. Description of the Prior Art
The structure disclosed in, for example, Japanese patent Publication No. 30592/1986 is known as a conventional action-changing structure of this kind for motion toys. The structure disclosed in this publication is formed as follows. First and second interlocking gears having different numbers of teeth are mounted on a slide shaft pivotably and fixedly, respectively. A change-over locking groove is formed in the side surface of the first interlocking gear which faces the second interlocking gear, in such a manner that this locking groove extends around the center of pivotal movement of the first interlocking gear in concentric relation therewith. A change-over locking projection is formed on the side surface of the second interlocking gear which faces the first interlocking gear, which locking projection is adapted to engage and disengage from the locking groove in accordance with the pivotal movement of the first interlocking gear. These first and second interlocking gears are meshed with a pivotable driving gear, a driving power source common thereto. A changeover gear adapted to engage and disengage from a relay gear, by which the power is transmitted to a motion mechanism, is mounted fixedly on the slide shaft, and a coiled spring constantly urging the second interlocking gear toward the first interlocking gear is also provided on the same slide shaft.
According to the structure disclosed in this publication, the first and second interlocking gears having different numbers of teeth are meshed with the driving gear, and the second interlocking gear is engaged with and disengaged from the first interlocking gear via the engaging and disengaging actions of the locking groove and locking projection in accordance with the pivotal movement of the driving gear by utilizing the difference between the rotational speeds of the first and second interlocking gears and the urging force of the coiled spring, to thereby move the slide shaft in the axial direction and advance and reverse the change-over gear in the same direction. The first and second interlocking gears having different numbers of teeth are engaged with and disengaged from each other as they are meshed with and turned by the common driving gear. Accordingly, in order that these gears are meshed and turned smoothly, it is necessary that these gears be manufactured with a high accuracy. Moreover, much labor is required to form locking groove and projection in and on the first and second interlocking gears of a small diameter. This often gives rise to the problems of the manufacturing cost and the strength of the parts, and causes an increase in the number of parts.